This invention relates to tufting machines and more particularly to a method and apparatus for selectively forming cut pile and loop pile having substantially the same pile height as the cut pile in the same row of stitching in a backing material.
In R. T. Card, U.S. Pat. No. 3,084,645, a method and apparatus for tufting cut pile and loop pile in the same row of stitching is disclosed. In spite of the enormous commercial success of that method and apparatus, and of the tufted product produced thereby, it has an inherent shortcoming that has limited it from even further success and acceptance of the tufted product produced. Because uncut loop pile is formed by backrobbing yarn from that loop to move a spring clip away from the point of the hook to allow the loop to be withdrawn from the hook while cut pile is not formed by backrobbing, it produces a tufted product having cut pile ends that project from the backing fabric more than the uncut loop pile. The backrobbing of the yarn is effected by a pattern controlled yarn feed attachment. Thus, the pile height of the fabric produced is not level, but varies with the pattern. The cut pile has a greater pile height than the shorter uncut pile which appears less dense. This effect distracts from the appearance of the tufted product and has limited its appeal.
As pointed out in the aforesaid U.S. Pat. No. 3,084,645 there have been other, but commercially unsatisfactory, approaches for patterning a fabric selectively with cut pile and loop pile. In McCutchen U.S. Pat. No. 2,879,728 selective loops on the hook are pushed off by a pattern controlled finger while others are allowed to stay on and are cut. Another proposal is illustrated in McCutchen U.S. Pat. No. 2,879,729 wherein each needle has two opposed hooks associated therewith, one with a knife. When cut pile is desired a loop is transferred from the hook without the knife to the one with the knife. Although these proposals illustrate even level cut and loop pile their shortcomings are readily apparent; simplicity and reliability being primary concerns of the tufted fabric industry.
An effective approach to obtaining even level cut and loop pile is disclosed in U.S. Pat. No. 4,134,347 of Jolley et al, assigned to the common assignee of the present invention, in which a pivotable gate member engagably cooperates with the bill of the hook to selectively open or close the passage from the bill to the hook blade of a seized loop. The loop is seized by the bill and the gate either allows or prevents a loop from moving beyond the bill to the closed end of the hook. Those loops that are allowed passage are cut, the other loops are shed by the bill. Setting of the stitches in the fabric draws both the cut and uncut loops to substantially the same level. A similar but different approach is disclosed in U.S. Pat. No. 4,185,569 of Inman, also assigned to the same assignee of the present invention. In these machines, a yarn feed pattern attachment for selectively controlling the yarn is not required.
Although the apparatus disclosed in the aforesaid Jolley et al, and Inman patents may provide satisfactory results, they have some shortcomings. Firstly, since each gate is individually controlled by pneumatic means or the like, a limitation on he minimum gauge or spacing between laterally adjacent hooks results. Thus, the gauge or spacing between adjacent tufts is larger or coarser than that which may be desirable for some commercially aesthetic carpet designs. Secondly, since the gate and control cylinders or the like are disposed beneath the bed of the tufting machine, the lint which results from the cutting of the yarn and the movement of the yarn on the hooks, tends to hinder the pivotal movement of the gate and additionally may effect the operation of the pneumatic cylinders. Thus, these "level-cut-loop" machines have been limited somewhat in their application.
In other known tufting machines, those machines known in the art as controlled needle tufting machines, the various needles may be selectively engaged and dispensed, in skip-stitch fashion in accordance with a program during each recipricatory cycle of the needle driving push rods. Basically, these machines render selective needles or groups of needles inoperative while the remainder of the needles are operative to pierce and penetrate the backing fabric upon each downward stroke of the push rods. Examples of these machines are illustrated in U.S. Pat. Nos. 3,115,856; 3,259,088; 3,881,432; 3,986,465 and 4,794,874. Such machines have been very successful, especially for producing bedspreads, and in the case of individually controlled needle tufting machines have been widely accepted for overtufting a design into a pretufted fabric, as illustrated in U.S. Pat. No. 4,693,190.
In these controlled needle tufting machines, each needle cooperates with its own respective loop seizing hook, and each hook cooperates with one needle. However, in Price copending U.S. application Ser. No. 07/179,073 filed on Apr. 8, 1988, (Notice of Allowance mailed 10/19/88), assigned to the same assignee as the present invention, a tufting machine having a pair of rows of spaced apart needles independently selectively driven into cooperation with hooks is disclosed, the machine in one form being capable of producing tufted fabric having half the gauge of conventional controlled needle machines by staggering the needles in one row relative to the needles in the other row and providing a loop seizing hook for cooperation with each needle.
Except for the loop pile fabric produced by the method disclosed in the aforesaid U.S. Pat. No. 4,794,874, all of the aforesaid controlled needle machines produce cut pile fabric. The prior art has not developed, nor is it believed that the prior art has even proposed, a tufting machine having individually controlled needles which can produce cut and/or loop pile selectively in the same row of stitching. Such a machine, since it does not utilize a yarn feed pattern attachment, would be capable of producing cut pile and loop pile having the same pile height as the cut pile, and would not have the disadvantages associated with machines having gated hooks.